- Neurotransmitters fit into receptor sites on the dendrites of neurons like a key fits into a lock

Synapse

- Space between the terminal buttons of one neuron and the dendrites of the next neuron

Receptor Sites

- Areas on a dendrite designed to receive a specific neurotransmitter

Threshold

- Level of neurotransmitters required to "fire" a neuron

Action Potential

- Electric charge that spreads down the length of a neuron after the threshold is achieved

- Travels like a bullet from a gun

All-or-None Principle

- Neuron either fires completely or it does not fire at all

- If the dendrites of a neuron receive enough neurotransmitters to push the neuron past its threshold, the neuron will fire completely every time

Neural Firing

- Electrochemical process

- Electricity travels within the cell (moves from the dendrites to the terminal buttons—called action potential), and chemicals (neurotransmitters) travel between cells in the synapse; electricity does not jump between the neurons

Excitatory Neurotransmitters

- Chemicals released from the terminal buttons of a neuron that excite the next neuron into firing

Inhibitory Neurotransmitters

- Chemicals released from the terminal buttons of a neuron that inhibit the next neuron from firing

Acetylcholine

- Associated with motor movement

- Lack of acetylcholine is associated with Alzheimer's disease

Dopamine

- Associated with motor movement and alertness

- Lack of dopamine is associated with Parkinson's disease; an overabundance is associated with schizophrenia

Endorphins

- Neurotransmitter associated with pain control

- Also involved in drug addiction

Serotonin

- Neurotransmitter associated with mood control.

- Lack of serotonin is associated with clinical depression.

Afferent Neurons (Sensory Neurons)

- Neurons that take information from the senses to the brain.

- Afferent neurons are responsible for transmitting neural impulses from the rest of the body to the brain.

Efferent Neurons (Motor Neurons)

- Neurons that take information from the brain to the rest of the body.

- Efferent neurons carry information that exits the brain.

Central Nervous System

- Part of the nervous system that consists of our brain and spinal cord.

- All the nerves are housed within bone (the skull and vertebrae).

Spinal Cord

- A bundle of nerves that run through the center of the spine.

- Transmits information from the rest of the body to the brain.

Peripheral Nervous System

- All the nerves in your body other than the brain and spinal cord nerves; all the nerves not encased in bone.

- The peripheral nervous system is divided into two categories: the somatic and the autonomic nervous systems.

Somatic Nervous System

- Controls voluntary muscle movements.

- The motor cortex of the brain sends impulses to the somatic nervous system, which controls the muscles that allow us to move.

Autonomic Nervous System

- Controls the automatic functions of the human body-heart, lungs, internal organs, glands, and so on.

- Controls responses to stress-the fight or flight response that prepares the body to respond to a perceived threat.

- Divided into two categories: the sympathetic and parasympathetic nervous systems.

Sympathetic Nervous System

- Mobilizes our body to respond to stress.

- Part of the nervous system that carries messages to the control systems of the organs, glands, and muscles that direct the body's response to stress.

- The alert system of the human body. It accelerates some functions (such as heart rate, blood pressure, and respiration) but conserves resources needed for a quick response by slowing down other functions (such as digestion).

Parasympathetic Nervous System

- Responsible for slowing down the body after a stress response.

- Carries messages to the stress response system that causes the body to slow down.

- Think of the parasympathetic nervous system as the brake pedal that slows down the body's autonomic nervous system.

Accidents

- Early psychologists studied accidents as a way to investigate brain function.

- Accidents resulting in injuries to specific brain areas (such as the Phineas Gage case study) helped psychologists get an idea about the function of each part of the brain.

Lesions

- Removal or destruction of part of the brain.

- Sometimes doctors decide that the best treatment for a certain condition involves surgery that will destroy or incapacitate part of the brain.

- This part of the cerebral cortex sends signals to our muscles, controlling our voluntary movements

- The top of the body is controlled by the neurons at the bottom of this cortex (by the ears0, progressing down the body as you go up the cortex

Parietal Lobes

- Located behind frontal lobe on the top of the brain

- Contain the sensory cortex (also known as the somato-sensory cortex), which is located right behind the motor cortex in the frontal lobe

Sensory Cortex

- Thin vertical strip of the cerebral cortex that receives incoming touch sensations from the rest of our body

- Organized similarly to the motor cortex

- Top of the sensory cortex receives sensations from the bottom of the body, progressing down the cortex to the bottom, which processes signals from our face and head.

Occipital Lobes

- Located at the very back of the brain, farthest from our eyes. This is somewhat anti-intuitive since one of the major functions of this lobe is to interpret messages from our eyes in our visual cortex

- Impulses from the retinas in our eyes are sent to the visual cortex to be interpreted

- Impulses from the right half of each retina are processes in the visual cortex in the right occipital lobe. Impulses from the left part of each retina are sent to the visual cortex in our left occipital lobe

Temporal Lobes

- Process sound sensed by our ears

- Sound waves are processed by the ears, turned into neural impulses, and interpreted in our auditory cortices

- Auditory cortex is not lateralized like visual cortices are. Sound received by left ear is processed in auditory cortices in both hemispheres

Brain Plasticity

- Parts of brain can adapt themselves to perform other functions if needed

- Cerebral cortex is made up of a complex network of neurons connected by dendrites that grow to make new connections

- Since dendrites grow throughout our lives, if one part of the brain is damaged, dendrites might be able to make new connections in another part of the brain that would be able to take over the functions usually performed by the damaged part of the brain

- Dendrites grow most quickly in younger children. Researchers know that younger brains are more plastic and are more likely to compensate for damage

Endocrine System

- System of glands that secrete hormones

- Affects many different biological processes in our bodies

Magnetic Resonance Imaging (MRI Scan)

- Uses magnetic fields to measure the density and location of brain material